F_VN_GetRoi

F_VN_GetRoi 1:

Gets the coordinates of the region of interest (ROI) within the image.

Syntax

Definition:

FUNCTION F_VN_GetRoi : HRESULT
VAR_INPUT
    ipSrcImage : ITcVnImage;
END_VAR
VAR_IN_OUT
    stRoi      : TcVnRectangle_UDINT;
END_VAR
VAR_INPUT
    hrPrev     : HRESULT;
END_VAR

F_VN_GetRoi 2: Inputs

Name

Type

Description

ipSrcImage

ITcVnImage

Source image

hrPrev

HRESULT

HRESULT indicating the result of previous operations (If SUCCEEDED(hrPrev) equals false, no operation is executed.)

F_VN_GetRoi 3: In/Outputs

Name

Type

Description

stRoi

TcVnRectangle_UDINT

Returns the coordinates of the region of interest

F_VN_GetRoi 4: Return value

HRESULT

Further information

The function F_VN_GetRoi indicates which Region Of Interest is currently set on the input image ipSrcImage. The information is required, for example, if points in the image are to be specified in relation to the total image or if the ROI is to be dynamically enlarged.

Application

The referencing of a point to the coordinates of the original image looks like this, for example:

hr := F_VN_ContourCenterOfMass(ipContour, aCenter, hr);
hr := F_VN_GetRoi(ipImageWork, stRoi, hr);
aCenter[0] := aCenter[0] + stRoi.nX;
aCenter[1] := aCenter[1] + stRoi.nY;

Related functions

Required License

TC3 Vision Base

System Requirements

Development environment

Target platform

PLC libraries to include

TwinCAT V3.1.4024.54 or later

PC or CX (x64) with PL50, e.g. Intel 4-core Atom CPU

Tc3_Vision